There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
Bill Gates Is Once Again the Richest Person in the World. A fresh list of the wealthiest people in the world is out, and is it any surprise who claimed the number one spot? Bill Gates, Microsoft co-founder and one the richest people in human history, once again comes out on top, with a net worth of $87.4 billion. Wealth-X, a wealth-tracking website, provided Business Insider with its newest figures on the assets of the ultra-rich.